Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756425AbdLVTId (ORCPT ); Fri, 22 Dec 2017 14:08:33 -0500 Received: from smtprelay.synopsys.com ([198.182.60.111]:57698 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750864AbdLVTIc (ORCPT ); Fri, 22 Dec 2017 14:08:32 -0500 From: Eugeniy Paltsev To: linux-snps-arc@lists.infradead.org Cc: linux-kernel@vger.kernel.org, Vineet Gupta , Alexey Brodkin , Rob Herring , Eugeniy Paltsev Subject: [RFC] ARC: setup cpu possible mask according to status field in dts Date: Fri, 22 Dec 2017 22:08:28 +0300 Message-Id: <20171222190828.29162-1-Eugeniy.Paltsev@synopsys.com> X-Mailer: git-send-email 2.9.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3060 Lines: 109 As we have option in u-boot to set CPU mask for running linux, we want to pass information to kernel about CPU cores should be brought up. So we patch kernel dtb in u-boot to set CPUs status. On linux boot we setup cpu possible mask according to status field in each cpu node. It is generic method according to ePAPR: status - a standard property describing the state of a CPU. This property shall be present for nodes representing CPUs in a symmetric multiprocessing (SMP) configuration. For a CPU node the meaning of the "okay" and "disabled" values are as follows: "okay" - The CPU is running; "disabled" - The CPU is in a quiescent state." Also we setup MCIP debug mask according cpu possible mask. Signed-off-by: Eugeniy Paltsev --- arch/arc/kernel/mcip.c | 10 ++++++++-- arch/arc/kernel/smp.c | 30 ++++++++++++++++++++++++++---- 2 files changed, 34 insertions(+), 6 deletions(-) diff --git a/arch/arc/kernel/mcip.c b/arch/arc/kernel/mcip.c index f61a52b..246481d 100644 --- a/arch/arc/kernel/mcip.c +++ b/arch/arc/kernel/mcip.c @@ -89,6 +89,8 @@ static void mcip_ipi_clear(int irq) static void mcip_probe_n_setup(void) { struct mcip_bcr mp; + u32 mcip_mask = 0; + int i; READ_BCR(ARC_REG_MCIP_BCR, mp); @@ -102,9 +104,13 @@ static void mcip_probe_n_setup(void) cpuinfo_arc700[0].extn.gfrc = mp.gfrc; + for (i = 0; i < NR_CPUS; i++) + if (cpu_possible(i)) + mcip_mask |= BIT(i); + if (mp.dbg) { - __mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, 0xf); - __mcip_cmd_data(CMD_DEBUG_SET_MASK, 0xf, 0xf); + __mcip_cmd_data(CMD_DEBUG_SET_SELECT, 0, mcip_mask); + __mcip_cmd_data(CMD_DEBUG_SET_MASK, 0xf, mcip_mask); } } diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c index efe8b42..ee8b20a 100644 --- a/arch/arc/kernel/smp.c +++ b/arch/arc/kernel/smp.c @@ -24,6 +24,8 @@ #include #include #include +#include +#include #include #include @@ -47,6 +49,29 @@ void __init smp_prepare_boot_cpu(void) { } +/* Mark cpu as possible if cpu status is "okay" or status absents */ +void __init smp_init_cpumask(void) +{ + const struct fdt_property *prop; + char fdt_cpu_path[25]; + unsigned int i, oft; + + for (i = 0; i < NR_CPUS; i++) { + sprintf(fdt_cpu_path, "/cpus/cpu@%u", i); + oft = fdt_path_offset(initial_boot_params, fdt_cpu_path); + prop = fdt_get_property(initial_boot_params, oft, "status", NULL); + + /* No status property == status OK */ + if (!prop) { + set_cpu_possible(i, true); + continue; + } + + if (!strcmp("okay", prop->data)) + set_cpu_possible(i, true); + } +} + /* * Called from setup_arch() before calling setup_processor() * @@ -58,10 +83,7 @@ void __init smp_prepare_boot_cpu(void) */ void __init smp_init_cpus(void) { - unsigned int i; - - for (i = 0; i < NR_CPUS; i++) - set_cpu_possible(i, true); + smp_init_cpumask(); if (plat_smp_ops.init_early_smp) plat_smp_ops.init_early_smp(); -- 2.9.3